<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>

  <div class="container">
    <div class="left"></div>
    <div class="right"></div>
  </div>
</body>
<style>
  .left {
    float: left;
    width: 100px;
    height: 50px;
    background-color: aqua;
  }

  .right {
    background-color: black;
    height: 50px;
    margin-left: 100px;


  }
</style>

</html>